Power control based on power controller configuration records

ABSTRACT

Power systems and methods for supplying direct current power to a server rack via a power shelf assembly that includes multiple power supply units (PSUs) and a power shelf controller (PSC) that ensures a correct configuration of PSUs, backup battery units (BBUs), and connection components using a power shelf configuration record. Upon a boot cycle of the PSC, the configuration identified in the power shelf controller is compared to an actual configuration of the components being connected between a server rack and the power shelf assembly to avoid providing power too soon and causing an overload of components for the server rack.

BACKGROUND

A datacenter typically contains a collection of computer servers andcomponents for the management, operation, and connectivity of thoseservers, including power management systems that provide continued powerfor operation of datacenter components in the event of interruption ofpower provided by a primary power source. Existing power managementsystems for datacenters, however, typically employ secondary powersources that are relatively large and expensive.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments in accordance with the present disclosure will bedescribed with reference to the drawings, in which:

FIG. 1 is a front view of a redundant uninterruptable power shelf systemmounted in a server rack for supplying direct current (DC) power toserver rack components via DC bus bars of the server rack, in accordancewith at least one embodiment;

FIG. 2 is a three-dimensional view illustrating a detachably mountableautomatic transfer switch and power supply unit (ATSPSU) and a powershelf assembly (PSA) of the power shelf system of FIG. 1, in accordancewith at least one embodiment;

FIG. 3 is a three-dimensional view illustrating a detachably mountablebattery module (BM) and a power shelf assembly (PSA) of the power shelfsystem of FIG. 1, in accordance with at least one embodiment;

FIG. 4 is a simplified schematic diagram illustrating exemplaryembodiments of the PSA of FIG. 1 using power supply units (PSUs), inaccordance with at least one embodiment;

FIG. 5 is a simplified schematic diagram illustrating exemplaryembodiments of the PSA of FIG. 1 using battery modules (BMs), inaccordance with at least one embodiment;

FIG. 6 is a simplified schematic diagram illustrating a datacenter powermanagement system that includes multiple instances of the PSA of FIG. 1,a management module, and a communication network, in accordance with atleast one embodiment;

FIG. 7 is a flow chart for a process of identifying whether a powershelf configuration record is present and if so transmitting parametersof the power shelf configuration record to complex programmable logicdevices associated with the power shelf assembly during a boot sequenceof the power shelf assembly and server rack, in accordance with at leastone embodiment;

FIG. 8 is a flow chart for a process of identifying that the expectedconfiguration of PSUs and connection components of the power shelfassembly, as identified in the power shelf configuration record, matchesthe actual configuration of these components, in accordance with atleast one embodiment; and

FIG. 9 is an example power shelf configuration record, in accordancewith at least one embodiment.

DETAILED DESCRIPTION

In the following description, various embodiments will be described. Forpurposes of explanation, specific configurations and details are setforth in order to provide a thorough understanding of the embodiments.However, it will also be apparent to one skilled in the art that theembodiments may be practiced without the specific details. Furthermore,well-known features may be omitted or simplified in order not to obscurethe embodiment being described.

Embodiments herein are directed to providing a power system forsupplying direct current (DC) to a server rack that includes a powershelf assembly (PSA), a power shelf controller (PSC), one or moredetachably mountable automatic transfer switch and power supply units(ATSPSUs), one or more detachably mountable battery modules (BMs),and/or one or more backup battery units (BBUs). Each of the one or moreATSPSUs is configured to generate DC power from alternating current (AC)input power and output the DC power to the DC bus bars of the serverrack. Each of the one or more BMs and/or BBUs is configured to providebackup DC power to the DC bus bars in the event of discontinuity in thesupply of the DC power to the DC bus bars by the ATSPSUs.

Each of the one or more ATSPSUs and each of the one or more BMs/BBUs canemploy an autonomous control process that can be used in the absence ofcommunication with other elements of the power system. For example, eachof the ATSPSUs can be configured to monitor voltage of a primary ACpower source and react to significant discontinuities in the voltage ofthe primary AC power source by discontinuing output of DC power to theDC bus bars. The one or more BMs/BBUs can monitor the voltage betweenthe DC bus bars and, in response to a drop in the voltage between the DCbus bars indicative of insufficient supply of DC power to the DC busbars by the one or more ATSPSUs, supply DC power to the DC bus bars fora period of time. Any suitable number of the one or more ATSPSUs can beconfigured to switch over to generating DC power from AC power suppliedby a secondary AC power source to supply DC power to the DC bus bars,for example, either in response to a drop in voltage between the DC busbars indicative of insufficient supply of DC power to the DC bus bars bythe one or more BMs/BBUs, or after a suitable time delay followingfailure of the primary AC power source. The one or more BMs/BBUs can beconfigured to, in response to detecting a sufficient voltage levelbetween the DC bus bars, charge at a conservative rate, which can be set(e.g., via firmware/software) so that upstream circuit breakers are nottripped under maximum loads.

Control of the power system can be augmented via communication betweenthe one or more ATSPSUs and the one or more BMs/BBUs. For example, astate of charge of the one or more BMs/BBUs can be communicated to theone or more ATSPSUs and, in response to the state of charge beingsufficient to power the server rack components for a suitable timeperiod, the one or more ATSPSUs can allow the BMs/BBUs to dischargewithout transferring to generating DC power via power supplied by thesecondary AC power source. The BMs/BBUs can communicate each of theirstates of charge with the other of the BMs/BBUs and decide to charge ordischarge separately or in unison. The one or more ATSPSUs cancommunicate the current power usage of the server rack components to theBMs/BBUs, which can use the current power usage to control recharging tomaximize the recharging of the BMs/BBUs without exceeding total maximumallowable power usage.

In accordance with at least one embodiment, control of the power systemcan be augmented via communication between the power shelf controller(PSC) of the PSA, the one or more ATSPSUs, and the one or more BMs/BBUs,or between a central management module and one or more PSAs of adatacenter power management system via an associated communicationnetwork. In various embodiments, the PSA may include non-volatile memoryfor storing and updating a power shelf configuration record thatincludes one or more parameters for an expected configuration of PSUs,BBUs, and whips (connection components) between a given PSA and a givenserver rack. In an embodiment, the power shelf configuration record mayidentify an expected configuration that includes a number of PSUs, anumber of BBUs, a number of connection components, and/or a data centertype. The power shelf configuration record may be updated when the PSCis installed into a PSA, as part of a new shelf integration, or during areplacement operation in a fleet of server racks/data centers.

In accordance with at least one embodiment, the PSC firmware accessesthe power shelf configuration record during a bootloader execution andpushes/transmits the parameters included in the power shelfconfiguration record to the complex programmable logic devices (CPLDs)associated with the ATSPSUs, BMs/BBUs, and/or associated CPLD registersof the PSA. A programmable component may be, for example a CPLD or otherintegrated circuit. By pushing or transmitting the parameters includedin the power shelf configuration record to the CPLD registers, the CPLDregisters are able to prevent executing a CPLD PS_ON Signal or commandused to turn on the PSUs and thereby prevent an Over Current Protection(OCP) shutdown fault while an operator connects the PSUs and connectioncomponents between the PSA and the server rack. In an embodiment, theparameters are utilized by the CPLD to compare the expected number ofPSUs and connection components to the actual configuration of PSUs andconnection components (e.g., those PSUs and connection componentsactually connected by the operator between the server rack and PSA). Inresponse to the comparison, the CPLD can set a flag register to indicatethe detection of a correct or incorrect configuration. The PSC firmwaremay generate a system event log (SEL) when it detects an incorrectconfiguration or an error condition. The SEL can be used by operators toupdate the configuration to the correct configuration given the type ofserver rack and the capabilities of the PSA.

FIG. 1 is a front view of a redundant uninterruptable power shelf systemmounted in a server rack for supplying direct current (DC) power toserver rack components via DC bus bars of the server rack, in accordancewith at least one embodiment. FIG. 1 includes a power system 10 mountedin a sever rack 12, in accordance with embodiments. The power system 10is configured to redundantly supply DC power to components mounted inserver rack 12 via DC bus bars 14, 16 of the server rack 12. The powersystem 10 includes a power shelf assembly (PSA) 18, automatic transferswitch and power supply units (ATSPSUs) 20, and battery modules (BMs)22. In some embodiments, the BMs may also be referred to as backupbattery units (BBUs). In the illustrated embodiment, each of the ATSPSUs20 and each of the BMs 22 is detachably mountable to the PSA 18 viainsertion through a front face of the server rack 12. A primary AC powersource input 24 and a secondary AC power source input 26 are operativelycoupled with the PSA 18, which operatively couples each of the primaryAC power source input 24 and the secondary AC power source input 26 witheach of the ATSPSUs 20 when mounted to the PSA 18. In accordance with atleast one embodiment, the PSA 18 may be pre-configured to pre-assembledwith a set number of connected PSUs and BMs. In such configurations, thePSC 28 may access the associated power shelf configuration record toensure a proper connection configuration is followed by an operatorusing connection components (whips) to connect the PSUs of the ATSPSUs20 to the server rack 12.

The ATSPSUs 20 and the BMs 22 are configured to redundantly supply powerto the DC bus bars 14, 16 for consumption by components mounted in theserver rack 12. Each of the ATSPSUs 20 are configured to generate DCpower from AC power received from either the primary AC power sourceinput 24 or the secondary AC power source input 26 via the PSA 18, andoutput the generated DC power to the DC bus bars 14, 16. Each of the BMs22 provides a backup source of DC power that is supplied to the DC busbars 14, 16 in the event of insufficient DC power being supplied to theDC bus bars 14, 16 by the ATSPSUSs 20. In accordance with at least oneembodiment, the PSA 18 may include a PSC 28 that is configured to accessa power shelf configuration record that identifies one or moreparameters for ensuring a correct configuration of ATSPSUs and BMs areconnected between the PSA 18 and the server rack 12. In an embodiment,the PSC 28 may be removed upon a boot sequence of the PSA 18 and theATSPSUSs 20 and BMs 22 can continue to generate DC power from AC powerreceived from either the primary AC power source input 24 or thesecondary AC power source input 26. The boot sequence of the PSC 28,using the power shelf configuration record, is configured such that upona correct configuration of ATSPSUs 20 and BMs 22 being connected to theserver rack 12, a CPLD of the PSA 18 may set a flag for continuous poweror power on signal (e.g., indicating that the PSU may be powered on) sothat the ATSPSUs 20 and BMs 22 continue to provide power to the serverrack 12. In various embodiments, the PSC 28 may communicate directlywith components of the PSA 18, such as by communicating directly withthe ATSPSU 20, associated PSUs, or BMs 22 to set flags or otherwiseexecute commands to provide power to the server rack 12. Although manyembodiments described herein depict a power shelf as having a formfactor that fits within a portion of a server rack, the power shelf canalso have other form factors that do not necessarily fit within theserver rack.

FIGS. 2 and 3 show a three-dimensional view further illustrating thepower system 10. FIG. 2 shows a three-dimensional view illustratingATSPSUs 20 mounted to the PSA 18 of the power system 10, which ismounted in the server rack 12. FIG. 3 shows a three-dimensional viewillustrating BMs 22 mounted to the PSA 18 of the power system 10, whichis mounted in the server rack 12. In the illustrated embodiment, sixATSPSUs 20 are arranged side-by-side in an upper row and three BMs 22are arranged side-by-side in a lower row below the upper row. In someembodiments, each of the ATSPSUs 20 and each of the BMs 22 can be “hot”mounted to and demounted from the PSA 18 while power is supplied to DCbus bars 14, 16 via the other mounted ATSPSUs 20 and/or BMs 22. In theillustrated embodiment, having six ATSPSUs 20, at 3 KVA each, provide 18KVA total, thereby exceeding a desired minimum of 15 KVA. Additionally,having six ATSPSUs 20 enable having two ATSPSUSs 20 on each of threephases of an AC power source. In accordance with at least oneembodiment, the power shelf configuration record may identify anexpected configuration of PSUs (e.g., a certain number of PSUs) that areto be utilized with a particular type of server rack and an expectednumber of connection components for connecting the PSUs to the serverrack 12. The expected configuration of PSUs may be less than the actualamount of PSUs or ATSPSUs 20 that are associated with the PSA 18. Forexample, the power shelf configuration may utilize an N+1 redundancy toensure that at least one extra ATSPSU is available for use by the PSA 18in response to a failed or malfunctioning ATSPSU of the ATSPSUs 20. Thepower shelf configuration record for a given PSA 18 may be updated orspecified differently for each type and configuration of server rack tomaintain the N+1 redundancy of associated ATSPSUs 20, BMs 22, andconnection components.

FIG. 4 is a simplified schematic diagram illustrating exemplaryembodiments of the PSA of FIG. 1 using power supply units (PSUs), inaccordance with at least one embodiment. The PSA 18 of FIG. 4 includes aPSA ATSPSU connector assembly 32 for each of the ATSPSUs 20. Each of theATSPSUs 20 includes an ATSPSU connector assembly 34 configured toconnect with a respective PSA ATSPSU connector 32.

The PSA 18 is configured to electrically connect each of the ATSPSUs 20with a primary AC power source, a secondary power source, and the DC busbars 14, 16. Each of the PSA ATSPSU connector assemblies 32 include aprimary AC power source connector 36, a secondary AC power sourceconnector 38, a DC power input connector 40, and a communicationconnector 42. The PSA 18 includes a primary AC power source inputconnector 44, which is electrically connected to each of the primary ACpower source connectors 36 and configured to receive AC power from aprimary AC power source. The PSA 18 includes a secondary AC power sourceinput connector 46 which is electrically connected to each of thesecondary AC power source connectors 38 and configured to receive ACpower from a secondary AC power source. The PSA 18 electrically couplesthe DC bus bars 14, 16 with each of the DC power input connectors 40 viaDC output leads 28, 30. The PSA 18 can have any suitable configuration,such as any suitable combination of conductors and connectors supportedin any suitable manner.

The PSA 8 is configured to communicatively couple the ATSPSUs 20 and theBMs 22. The communication connectors 42 are communicatively coupled viaa communication bus included in the PSA 18 to enable communicationbetween each of the ATSPSUs 20 and each of the BMs 22, the power shelfcontroller 62, or one or more CPLDs implemented within the PSA 18 (notpictured). Any suitable communication connector can be used for thecommunication connector 42. For example, an RJ45 connector can be usedas the communication connector and Ethernet networking used forcommunication between the ATSPSUs 20, the BMs 22, the power shelfcontroller 62, and the CPLDs. Although many of the disclosed embodimentsdescribe using CPLDs for various functions, further embodiments useother integrated circuits (e.g., processors, field-programmable gatearrays (FPGAs), application-specific integrated circuits (ASICs)) alongwith or in place of the CPLDs. Additionally, the power shelf controller62 comprises, for example, a microcontroller, a processor, a CPLD, FPGA,ASIC, or other integrated circuit.

Each of the ATSPSUs 20 includes an automatic transfer switch (ATS) 48, apower supply unit (PSU) 50, an ATSPSU controller 52, and the ATSPSUconnector assembly 34. The ATSPSU connector assembly 34 includes aprimary AC power source input connector 54, a secondary AC power sourceinput connector 56, a DC power output connector 58, and a communicationconnector 60. Connector 54 is configured to connect with connector 36.Connector 56 is configured to connect with connector 38. Connector 58 isconfigured to connect with connector 40. Connector 60 is configured toconnect with connector 42. The ATS 48 is electrically connected witheach of connectors 54, 56 so as to be electrically connected with eachof the primary and secondary AC power sources via the PSA 18. The ATS 48is configured to selectively supply AC power to the PSU 50 from eitherthe primary AC power source or the secondary AC power source asdescribed herein. The PSU 50 generates DC power from the AC powerreceived from the ATS 48 and outputs the generated power to the DC busbars 14, 16 via the DC power output connector 58 and the PSA 18.

The ATSPSU controller 52 is operatively connected with the ATS 48 andthe PSU 50 and controls operation of the ATS 48 and the PSU 50 asdescribed herein. In many embodiments, the ATSPSU controller 52 isconfigured to (a) monitor a voltage of the primary AC power source(e.g., a line to neutral voltage of the primary AC power source); (b)monitor a voltage of the secondary AC power source (e.g., a line toneutral voltage of the secondary AC power source); (c) monitor voltagebetween the DC bus bars; (d) control the PSU 50 to terminate output ofDC power from the PSU 50 to the DC power output connector 58 in responseto detecting a qualifying voltage drop instance in the primary AC powersource as described herein when the ATS 48 is supplying AC power to thePSU 50 from the primary AC power source or a qualifying voltage dropinstance in the secondary AC power source as described herein when theATS 48 is supplying AC power to the PSU 50 from the secondary AC powersource; and (e) control the ATS 48 to switch between supplying AC powerto the PSU 50 between the primary AC power source and the secondary ACpower source in response to the monitored voltages of the primary andsecondary AC power sources and the monitored voltage between the DC busbars as described herein.

The PSA 18 can optionally include a power shelf controller 62 and/or anexternal communication port 64. The power shelf controller 62 can beconfigured to monitor total electrical power consumed by the componentsof the server rack 12 and coordinate operation of the ATSPSUs 20 and theBMs 22 in accordance with the total electrical power consumed andconstraints on the amount of AC power that can be obtained from each ofthe primary and secondary AC power sources. The external communicationport 64 can be used to network the ATSPSUs 20 and the BMs 22 and/or thepower shelf controller 62 with an external power management module via adata center network so that the operation of the power system 10 can becontrolled in conjunction with simultaneous control of one or more otherpower systems 10 supplying power to other server racks 12 powered by theprimary and secondary AC power sources so as to better control totalloads placed on one or both of the primary and secondary AC powersources. In some embodiments, the power shelf controller 62 may beconfigured to access a power shelf configuration record stored innon-volatile memory 74 of the PSA 18. As described herein, the powershelf configuration record may include one or more parameters thatidentify an expected configuration of ATSPSUs 20. BMs 22, and connectioncomponents (e.g., whips) between the PSA 18 and a given server rack 12.

The power shelf controller 62 may be configured to transmit theparameters of the power shelf configuration record stored in thenon-volatile memory 74 to the ATSPSU controller 52 or other CPLDsassociated with the ATSPSUs 20 and BMs 22. The CPLDs can compare thereceived parameters of the expected configuration of PSUs 50, ATSPSUs20, BMs 22 and an actual configuration of the PSUs 50, ATSPSUs 20, BMs22 being connected by an operator between the PSA 18 and server rack asindicated by PSA ATSPSU connector assemblies 32 and ATSPSU connectorassembly 34. In accordance with at least one embodiment, the power shelfcontroller 62 may be configured to prevent energization of thecomponents of the server rack 12 until a correct configuration ofATSPSUs 20, BMs 22, and connection components has been establishedaccording to the parameters included in the power shelf configurationrecord. Once a correct configuration of components between the PSA 18and server rack 12 has been identified then the power shelf controller62 may provide instructions or otherwise communicate with the associatedCPLDs of the ATSPSUs 20 and BMs 22 to begin providing power to theserver rack 12. In various embodiments, the power shelf controller 62may be removed once the power on signals or instructions have beenprovided to the ATSPSUs 20 and BMs 22 for further updating or modifying.Further, the ATSPSUs 20 and/or BMs 22 may be swapped out withoutinterrupting the power provided to the server rack 12. Swapping outcomponents (a swap out operation) of a server rack 12, such as theATSPSUs 20 and/or BMs 22 may include replacing one or more ATSPSUs 20and/or BMs 22 in the server rack for another ATSPSU 20 or BM 22. A swapout operation may include receiving a SEL, a notification, or otherinformation that indicates that a component of the server rack 12 and/orPSA 18 should be replaced (e.g., swapping out a given ATSPSU 20 or BM 22for another ATSPSU 20 or BM 22 such as in the case of a componentmalfunction). The power shelf controller 62 and/or the CPLDs associatedwith the ATSPSUs 20 and BMs 22 may be configured to periodically poll orcommunicate that the correct configuration of components are connectedand being utilized between the server rack 12 and PSA 18 (e.g., correctnumber of ATSPSUs 20, BMs 22, and connection components). As such, aslong as the correct number of ATSPSUs 20, BMs 22, and connectioncomponents are being utilized after a swap or switch out of othercomponents of the PSA 18, server may be uninterrupted for customersutilizing the data center and server rack 12.

FIG. 5 is a simplified schematic diagram illustrating an embodiment ofthe PSA 18 and BMs 22 of the power system 10. The PSA 18 includes a PSABM connector assembly 66 for each of the BMs 22. Each of the BMs 22includes a BM connector assembly 68 configured to connect with arespective PSA BM connector assembly 66.

The PSA 18 is configured to electrically connect each of the BMs 22 withthe DC bus bars 14, 16. Each of the PSA BM connector assemblies 66includes a DC power connector 40, and a communication connector 42. ThePSA 18 electrically couples the DC bus bars 14, 16 with each of the DCpower connectors 40 via DC output leads 28, 30.

Each of the BMs 22 includes one or more battery cells 70 and a BMcontroller 72, and the BM connector assembly 68. The BM connectorassembly 68 includes a DC power connector 58 and a communicationconnector 60. Connector 58 is configured to connect with connector 40.Connector 60 is configured to connect with connector 42.

The BM controller 72 controls operation of the BM 22. In manyembodiments, the BM controller 72 is configured to (a) monitor voltagebetween the DC bus bars; and (b) control discharging and charging of theone or more battery cells 70 as described herein. The PSA 18 of FIG. 5includes a power shelf controller 62 and non-volatile memory 74 which isconfigured to perform the same capabilities as those described abovewith reference to FIG. 4 including storing and accessing a power shelfconfiguration record that can be utilized to ensure a correctconfiguration of BMs 22 and connection components have been utilizedwhen attaching the PSA 18 to server rack 12 prior to providing a poweron signal to the BMs 22.

FIG. 6 is a simplified schematic diagram illustrating a datacenter powermanagement system 100 that includes multiple instances of the powersystem 10, a management module 102, a communication network 104, and auser interface module 106 in accordance with some embodiments. In thepower management system 100, the management module 102 is configured tocontrol operation of the individual power systems 10 so as to avoidoverloading the secondary AC power source in the event of a failure ofthe primary AC power source. For example, the management module 102 cancontrol which of the ATSPSUs 20 in each of the power systems 10 switchto generating DC power via AC power supplied by the secondary AC powersource, thereby controlling the total load placed on the secondary ACpower source to avoid overloading the secondary AC power source. Themanagement module 102 can also monitor total data center powerconsumption level and limit charging of the BMs in each of the powersystems 10 to a suitable rate in view of the total data center powerconsumption level to avoid overloading either of the secondary AC powersource and the primary AC power source. The user interface 106 isconfigured to display system operational parameters to a user and toaccept input from a user for configuration and operation of the powermanagement system 100. In at least some embodiments the modules 102, 106can be implemented as software, running on one or more processors, andimplementing one or more of the methods described herein.

In many embodiments, the power system 10 and the power management system100 provide a variety of benefits relative to existing power supplysystems. For example, the power system 10 and the power managementsystem 100 employ reduced layers of redundancy relative to existingpower supply systems as a result of each of the power systems 10including multiple ATSPSUs 20 and one or more battery modules 22. Thepower system 10 is configured to continue to supply DC power for aperiod of time in the event of failure of one or both of the first andsecond AC power sources, thereby providing immunity to many potentialfailures of the first and second AC power sources. The power system 10and the power management system 100 can be employed to reduce costs andproduction capacity constraints that limit growth in a datacenter byusing standardized components (e.g., ATSPSUs 20, BMs 22) that can beobtained from multiple sources. In many embodiments, the power system 10includes multiple ATSPSUs 20 (e.g., 2, 3, 4, 5, 6, or more) and multipleBMs 22 (e.g., 2, 3, or more), the power system 10 can continue to supplyDC current even in the event of a failure of one of the ATSPSUs 20 orone of the BMs 22, thereby helping to reduce the number of customersaffected when a failure does occur. The power system 10 and/or the powermanagement system 100 can be configured to reflect a desired tradeoffbetween autonomous operation to avoid failure propagation and networkedoperation to enable the actions to be based on an overall operationalstate. In many embodiments, the power system 10 is configured to reactto intermittent peaks in power demand via discharging the BMs 22,thereby isolating the primary AC power source from being impacted andallowing corresponding reduction in the size and cost of the primary ACpower system relative to existing power supply systems. For example,each of the PSUs 50 can be limited to a maximum power output therebyforcing the BMs 22 to discharge in response to intermittent power demandexceeding the combined maximum output of the PSUs 50. The power system10 that utilizes the PSA 18 with ATSPSUs 20 and BMs 22 stored on the PSA18 itself rather than on the server rack 12 provides more physical spaceon the server rack 12 for other components such as additional harddrives, or cooling systems. Further, the power shelf controller 62,along with the power shelf configuration records, enables the firmwarefor the ATSPSUs 20 and BMs 22 to be updated without disconnecting thePSA 18 from the server rack 12. Components of the PSA 18 such asindividual ATSPSUs 20 or BMs 22 can be swapped out in case ofmalfunctions or based on other health status information obtained by thepower shelf controller 62 and/or ATSPSU controller 52/battery modulecontroller 72. The ATSPSUs 20 and BMs 22 can individually or one at atime update their firmware to avoid shutting down a server rack 12 byutilizing the configuration described herein for PSA 18 and server rack12.

In many embodiments, the power system 10 and/or the power managementsystem 100 are configured to control operation based on a variety ofinputs. The variety of inputs can include any suitable combination of(a) whether the primary AC power source is in an operational state(e.g., providing AC power having a suitable voltage profile) or in afailed state (e.g., failing to provide AC power having a suitablevoltage profile), (b) whether the secondary AC power source is in anoperational state (e.g., providing AC power having a suitable voltageprofile) or in a failed state (e.g., failing to provide AC power havinga suitable voltage profile), (c) the voltage between the DC bus bars 14,16, which can be used to detect failure of a PSU 50 or a BM 22, and canbe used to balance the output of the PSUs 50 or the BMs 22 using droopcontrol (e.g., as described herein) (d) amount of DC current supplied tothe DC bus bars 14, 16, (e) amount of current being supplied by the DCbus bars 14, 16 to each load, (f) the state of charge of the BMs 22, (g)operational time remaining (e.g., seconds) via power supplied by the BMs22 or a combination of the BMs 22 and the secondary AC power source, and(h) total amount of load being serviced by the secondary AC powersource, which can be used to determine residual capacity available toservice additional loads that are candidates for being serviced via thesecondary AC power source, for example, as a result of prolonged failureof the primary AC power source.

In many embodiments, the power system 10 and/or the power managementsystem 100 are configured to control operation based on a variety ofpriorities and constraints. For example, the power system 10 and/or thepower management system 100 can be configured to prioritize servicing ofa certain load(s) over another load(s) for any suitable reason, such asa customer(s) paying more for better reliability/availability/immunityto outages. For example, the power system 10 and/or the power managementsystem 10 can be configured to decide not to switch over to supplying aload via power received from the secondary AC power source if the loadat risk is low priority and the secondary AC power source is alreadyclose to being overloaded. The charging of the BMs 22 can be constrainedto prevent exceeding the capacity of the primary AC power source in viewof the combined power draw of loads being serviced by the primary ACpower source. The charging of the BMs 22 can also be constrained toprevent exceeding the capacity of the secondary AC power source in viewof the combined power draw of loads being serviced by the secondary ACpower source. The number of PSUs 50 supplied power from the secondary ACpower source can be constrained to prevent exceeding the capacity of thesecondary AC power source in view of the combined power draw of loadsbeing serviced by the secondary AC power source.

In many embodiments, the power system 10 and/or the power managementsystem 100 can be configured to achieve various objectives. For example,the various objectives can include providing power to most (if not all)loads during a utility power outage. The objectives can include keepingthe BMs 22 fully charged when possible (e.g., recharging the BMs 22 asfast as possible following discharge of the BMs 22) to be in a state ofreadiness for a potential failure of the primary AC power source. Theobjectives can include avoiding supplying power to the loads from thesecondary AC power source as much as possible so that the secondary ACpower source has residual capacity available to additional load(s). Theobjectives can include sharing loads by the PSUs 50 of the power system10 so as to operate the PSUs 50 at an output level for which the PSUs 50are most efficiently operated. For example, one or more PSUs 50 can bedeactivated so as to boost the load handled by the remaining PSUs 50 toan output level in which the remaining PSUs 50 operate more efficiently.In some embodiments, the power system 10 and/or the power managementsystem 100 can be configured to capture and report events regarding thecomponents of the PSA 18 and server rack 12. For example, as describedabove during the connection by an operator between the PSA 18 and serverrack 12 an incorrect configuration may be utilized (e.g., incorrectnumber of ATSPSUs 20, BMs 22, and connection components based on theparameters included in an associated power shelf configuration record).In such cases, the power shelf controller 62 is configured to preventpowering on the server rack 12 and generate a system event log that canbe transmitted to the power management system 100 for correction by anoperator. Other events such as individual hardware failures or healthinformation for components (such as relay status or temperatureinformation for components) of the PSA 18 may be captured and reportedin system event lots for correction via the power management system 100.In accordance with at least one embodiment, the PSA and/or PSC mayinclude volatile memory for temporarily storing a power shelfconfiguration record that is communicated by the management module 102,via network 104, to the power system 10 and PSA and/or PSC. During theboot load operation of the corresponding PSA and/or PSC, the power shelfconfiguration record can be accessed in the volatile memory andconfiguration checks between an expected number of connections betweenthe PSA and server rack can be compared to the actual number ofconnections as described herein.

FIG. 7 is a flow chart for a process of identifying whether a powershelf configuration record is present and if so transmitting parametersof the power shelf configuration record to complex programmable logicdevices associated with the power shelf assembly during a boot sequenceof the power shelf assembly and server rack, in accordance with at leastone embodiment. In various embodiments, the power shelf controllerand/or the power shelf assembly may include a baseboard managementcontroller (BMC) or other processor. The power shelf controller andbaseboard management controller are configured to prevent energizationof the bus bars of the server rack based on an expected power shelfconfiguration and an actual power shelf configuration. For example, theactual power shelf configuration includes the connection componentsutilized by an operator attaching the power shelf assembly to the serverrack (e.g., number of whips connected between the PSA and server rackthat indicates the number of PSUs and BBUs activated as a result ofusing the connection components between the server rack and the PSA). Inthe process 700 the baseboard management controller enters a boot loaderenvironment or other startup process at 702. At 704, the power shelfcontroller attempts to read the power shelf configuration record from anassociated storage space such as the non-volatile memory 74 of FIGS. 4and 5 to identify the parameters that indicate the correct configurationfor a given power shelf assembly and server rack. In the process 700, itis determined whether the power shelf configuration record is present at706 by identifying whether a data object that corresponds to the powershelf configuration record is stored or maintained in the associatedstorage (e.g., non-volatile memory 74). For example, a read file commandmay be executed and if the file is found, a found record response may bereceived, whereas if the record is not present a file not found responsemay be received. If the power shelf configuration record is present thenthe process continues at 708 by checking the configuration of ATSPSUs20, BMs 22, and connection components between the PSA 18 and server rack12 according to the parameters included in the power shelf configurationrecord. In some embodiments, checking the configuration between the PSA18 and the server rack 12 includes identifying a number of connectioncomponents actually connected between the server rack 12 and PSA 18 asindicated by whether the connection components are utilized to connectcomponents of the server rack 12 to the PSA 18. The connectioncomponents, if connected, will result in a certain number of ATSPSUs 20and BMs 22 receiving current or power. As described herein, the powershelf configuration record includes information that indicates anexpected number of connection components, ATSPSUs 20 and BMs 22 to beconnected during a connection process by an operator when the operatoris connecting the PSA 18 to the server rack 12. The information aboutthe expected ATSPSUs 20, BMs 22, and connection components is includedin the power shelf configuration record and is customized for aparticular server rack or server rack type. As such, any unexpectedconfiguration (e.g., incorrect number of connection components utilizedresulting in an incorrect amount of ATSPSUs 20 and BMs 22 attempting tobe used for the server rack) can result in error flags being set. Inaccordance with at least one embodiment, at 708, if the actualconfiguration (e.g., connection components being utilized with ATSPSUs20 and BMs 22) between the server rack 12 and PSA 18 is different fromthe expected configuration as indicated by the power shelf configurationrecord (Invalid), one or more error flags are set and the processcontinues to the BMC boot 712 where a record of the error flags may begenerated and provided to an operator to address the incorrectconfiguration. In some embodiments, at 708, if the actual configurationbetween the server rack 12 and PSA 18 is correct as indicated by theassociated power shelf configuration record (Valid) the processcontinues at 710. If the record is not present at 706 or once theconfiguration has been checked at 708, the power shelf controller isconfigured to update CPLD registers of the ATSPSUs 20 and BMs 22 withthe power shelf configuration record at 710 (e.g., update, transmit, orotherwise communicate the power shelf configuration record from thestorage of the PSA 18 to the CPLD registers of the ATSPSUs 20 and BMs22). Once the configuration has been checked and/or the power shelfconfiguration record has been transmitted or otherwise communicated tothe CPLD registers of the ATSPSUs 20 and BMs 22, the baseboardmanagement controller continues with the booting process for the PSA 18.Although some of the disclosed embodiments describe using CPLD registersto store information from the configuration record, in furtherembodiments the information can be stored in other forms of memory(e.g., RAM, ROM, Flash RAM, processor registers) in the ATSPSUs, BMs, orother components.

FIG. 8 is a flow chart for a process of identifying that the expectedconfiguration of power supply units (PSUs) and connection components ofthe power shelf assembly and server rack, as identified in the powershelf configuration record, matches the actual configuration of thesecomponents, in accordance with at least one embodiment. The process 800begins at 802 by identifying that the baseboard management controller orother component has completed a boot up operation (e.g., after theprocess 700 is complete). At 804 of the process 800 it is determinedwhether the bus bars of server rack 12 are on by receiving an indicationof power or current being provided to the bus bars of the server rack12. If the bus bars of server rack 12 are on, the process 800 concludesat 806 by periodically (e.g., once a day) checking the status/health ofcomponents of the PSA 18, as well as periodically identifying whetherthe correct configuration is being utilized between the PSA 18 andserver rack 12 based on input from the components such as the ATSPSUs 20and BMs 22.

However, if the bus bar is not on at 804, the process continues at 808by checking whether the correct number of PSUs or ATSPSUs 20 areconnected at 808 based on the power shelf configuration record pushed tothe ATSPSUs 20 during process 700 described in FIG. 7 (as represented by“Check PSU_NUM”, which represents an abbreviation for “check the numberof PSUs” in FIG. 8). If the power shelf configuration record is notpresent and therefor does not indicate the expected number of ATSPSUs20, then the process 800 includes generating a “record not found” systemevent log (SEL) at 810 (as represented by “Assert ‘Record’ not presentSEL”, which represents an abbreviation for “generate a SEL identifyingthat the power shelf configuration record is not present”). If the powershelf configuration record is present at 808 then the process includesreading the PSU capacity (e.g., 100 watts, 200 watts, or anothercapacity) from the PSU FRUIDs (field-replaceable unit identifier) at812. The process 800 includes deciding or determining 816 whether thereis a “mixed” PSU capacity, indicating that not all of the expected PSUshave been connected between PSA 18 and server rack 12. In this case, a“hold power for all PSU” command 814 is executed by the power shelfcontroller 62 and/or baseboard management controller. This commandcauses the PSUs to not distribute power. In the process 800, if there isnot a mixed capacity at 816, the process continues at 818 by determiningwhether there is a match or correct number of connection components(whips) being utilized for the expected number of PSUs. As describedherein, determining whether there is a match or correct number ofconnection components (whips) being utilized for the expected number ofPSUs includes using indicators or data identifying an actual number ofwhips connected between the PSA 18 and server rack 12 which is comparedto the expected number of whips to be connected between a given PSA 18and server rack 12 as indicated by the power shelf configuration record.In FIG. 8, at 818, if the there is a match or correct number ofconnection components (whips), then a flag for a match between therecord and components is set as indicated by the “MATCH_FLG” decision at818 of FIG. 8. If the incorrect number of connection components isidentified at 818, then the process includes at 820 generating a “checkwhips” system event log (SEL) that can be communicated to an operator ofpower management system 100 (as represented by the “AssertCHECK_PSU_WHIPS SEL 820” of FIG. 8 that represents generating a SEL thatidentifies an incorrect configuration between the PSU and WHIPS asindicated by the power shelf configuration record). In the process 800,if the number of ATSPSUs 20 and connection components matches theexpected number of ATSPSUs 20 and connection components identified inthe power shelf configuration record, then the process 800 proceeds at822. At 822 the process sets the CPLD command, or executes by the CPLD,a “power on” command for all associated ATSPSUs 20 and BMs 22 of a givenPSA 18. This causes the ATSPSUs 20 and BMs 22 to provide power to anattached server rack 12. The process 800 continues at 824 by identifyingwhether an “auto on” flag has been set for the components of PSA 18 and,if not, returning to step 808. The process returns to step 808 toredundantly check the configuration record and process through steps810-822 to identify a match between expected components as identified inthe power shelf configuration record and the actual number of connectedcomponents between the server rack 12 and PSA 18. However, if the autoon flag has been set for the components of PSA 18, the process concludesat 826 by executing a command to turn on all connected ATSPSUs 20.

FIG. 9 is an example power shelf configuration record, in accordancewith at least one embodiment. The power shelf configuration record 900includes fields 902, lengths 904, values 906, and remarks 908 for theparameters included in an exemplary power shelf configuration record. Itshould be noted that although FIG. 9 depicts the remarks 908 as part ofthe power shelf configuration record 900, in some embodiments theremarks may not be part of the power shelf configuration 900. The firstfield 902 at 910 identifies a record type which in this case, asindicated by the remark 908 identifies that this record is a power shelfconfiguration record. In the depicted embodiment, the record type 910has a length 904 of 0x01 (hexadecimal) byte and a value 906 of 0xC0. Insome embodiments, the power shelf configuration record 900 may include arecord checksum 912 and a header checksum 914. In accordance with atleast one embodiment, the record checksum 912 and header checksum 914may be utilized to identify that a correct power shelf configurationrecord is being utilized for a given server rack and/or for securitypurposes to identify a correct originating author of the power shelfconfiguration record 900. In various embodiments, the record checksum912 and header checksum 914 are utilized to determine the integrity ofthe power shelf configuration record 900. The power shelf configurationrecord 900 includes a data center type 916 field 902 with bitidentifiers 918 that are associated with different data center types.For example, the bit identifiers 918 may be an unsigned 8-bit integer inhexadecimal format that represents a data center type to indicate thetype of data center that the associated power shelf assembly is to beconnected to in a data center. This may be useful if, for example, aparticular model of power shelf is used in data centers that havediffering electrical systems or requirements. The power shelfconfiguration record 900 includes an indication of a number of whips 920(or connection components) that are to be utilized given the number ofPSUs 924. The remarks 908 section for the number of whips 920 includesan unsigned 8-bit integer in hexadecimal format that represents thetotal number of whips in the power shelf assembly that should beutilized to connect the correct number of PSUs 924 for a given type ofdata center 918. The remarks 908 for the number of PSUs 924 field 902includes an unsigned 16-bit integer in hexadecimal format thatrepresents the total number of expected or installed PSUs or ATSPSUs inpower shelf assembly for a given data center type 918.

The embodiments that describe the datacenter power management system orother embodiments that describe utilizing a network may utilize at leastone network that would be familiar to those skilled in the art forsupporting communications using any of a variety ofcommercially-available protocols, such as Transmission ControlProtocol/Internet Protocol (“TCP/IP”), Open System Interconnection(“OSI”), File Transfer Protocol (“FTP”), Universal Plug and Play(“UpnP”), Network File System (“NFS”), Common Internet File System(“CIFS”), and AppleTalk. The network can be, for example, a local areanetwork, a wide-area network, a virtual private network, the Internet,an intranet, an extranet, a public switched telephone network, aninfrared network, a wireless network, and any combination thereof.

The power shelf assembly and/or power shelf controller can include avariety of data stores and other memory and storage media as discussedabove. These can reside in a variety of locations within the power shelfassembly, such as on a storage medium local to (and/or resident in) oneor more of the computers of the power shelf assembly or remote from anyor all of the computers across the network (e.g., the managementmodule). In a particular set of embodiments, the information may residein a storage-area network (“SAN”) familiar to those skilled in the art.Similarly, any necessary files for performing the functions attributedto the computers, servers, or other network devices may be storedlocally and/or remotely, as appropriate. Where a system includescomputerized devices, each such device can include hardware elementsthat may be electrically coupled via a bus, the elements including, forexample, at least one central processing unit (“CPU”), at least oneinput device (e.g., a mouse, keyboard, controller, touch screen, orkeypad), and at least one output device (e.g., a display device,printer, or speaker). Such a system may also include one or more storagedevices, such as disk drives, optical storage devices, and solid-statestorage devices such as random access memory (“RAM”) or read-only memory(“ROM”), as well as removable media devices, memory cards, flash cards,etc. The storage media may be non-transitory.

Such devices also can include a computer-readable storage media reader,a communications device (e.g., a modem, a network card (wireless orwired)), an infrared communication device, etc.), and working memory asdescribed above. The computer-readable storage media reader can beconnected with, or configured to receive, a computer-readable storagemedium, representing remote, local, fixed, and/or removable storagedevices as well as storage media for temporarily and/or more permanentlycontaining, storing, transmitting, and retrieving computer-readableinformation. The system and various devices also typically will includea number of software applications, modules, services, or other elementslocated within at least one working memory device, including anoperating system and application programs, such as a client applicationor Web browser. It should be appreciated that alternate embodiments mayhave numerous variations from that described above. For example,customized hardware might also be used and/or particular elements mightbe implemented in hardware, software (including portable software, suchas applets), or both. Further, connection to other computing devicessuch as network input/output devices may be employed.

Storage media computer readable media for containing code, or portionsof code, can include any appropriate media known or used in the art,including storage media and communication media, such as but not limitedto volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology for storage and/or transmissionof information such as computer readable instructions, data structures,program modules, or other data, including RAM, ROM, ElectricallyErasable Programmable Read-Only Memory (“EEPROM”), flash memory or othermemory technology, Compact Disc Read-Only Memory (“CD-ROM”), digitalversatile disk (DVD), or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage, or other magnetic storage devices,or any other medium which can be used to store the desired informationand which can be accessed by a system device. Based on the disclosureand teachings provided herein, a person of ordinary skill in the artwill appreciate other ways and/or methods to implement the variousembodiments.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense. It will, however, beevident that various modifications and changes may be made thereuntowithout departing from the broader spirit and scope of the disclosure asset forth in the claims.

Other variations are within the spirit of the present disclosure. Thus,while the disclosed techniques are susceptible to various modificationsand alternative constructions, certain illustrated embodiments thereofare shown in the drawings and have been described above in detail. Itshould be understood, however, that there is no intention to limit thedisclosure to the specific form or forms disclosed, but on the contrary,the intention is to cover all modifications, alternative constructions,and equivalents falling within the spirit and scope of the disclosure,as defined in the appended claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the disclosed embodiments (especially in thecontext of the following claims) are to be construed to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms (i.e., meaning“including, but not limited to,”) unless otherwise noted. The term“connected” is to be construed as partly or wholly contained within,attached to, or joined together, even if there is something intervening.Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate embodiments of the disclosure anddoes not pose a limitation on the scope of the disclosure unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe disclosure.

Disjunctive language such as the phrase “at least one of X, Y, or Z,”unless specifically stated otherwise, is intended to be understoodwithin the context as used in general to present that an item, term,etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y,and/or Z). Thus, such disjunctive language is not generally intended to,and should not, imply that certain embodiments require at least one ofX, at least one of Y, or at least one of Z to each be present.

Various embodiments of this disclosure are described herein, includingthe best mode known to the inventors for carrying out the disclosure.Variations of those embodiments may become apparent to those of ordinaryskill in the art upon reading the foregoing description. The inventorsexpect skilled artisans to employ such variations as appropriate and theinventors intend for the disclosure to be practiced otherwise than asspecifically described herein. Accordingly, this disclosure includes allmodifications and equivalents of the subject matter recited in theclaims appended hereto as permitted by applicable law. Moreover, anycombination of the above-described elements in all possible variationsthereof is encompassed by the disclosure unless otherwise indicatedherein or otherwise clearly contradicted by context.

What is claimed is:
 1. A power system for supplying direct current (DC)power to a server rack, the power system comprising: a power shelfassembly (PSA) configured to be mounted in the server rack andincluding: a power supply unit (PSU) configured to output DC power to DCbus bars of the server rack; a power shelf controller (PSC) configuredto: store a power shelf configuration record that includes parametersfor a particular type of the server rack, the parameters of the powershelf configuration record comprising a number of whips, a number ofPSUs, a PSU capacity, or a data center type in which the server rack isinstalled; prevent energization of the DC bus bars of the server rackbased on a power shelf configuration associated with the power shelfassembly and a power sequencing of the PSU; and transmit the parametersto components of the PSA; a processor that is configured to: receive theparameters in response to a bootloader execution of the PSC; using theparameters, make a comparison of an expected number of connectioncomponents between the PSA and the server rack and an actualconfiguration of the connection components between the PSA and a serverof the server rack; and prevent the PSU from turning on based on thecomparison.
 2. The power system of claim 1, wherein the processor or thePSC is further configured to identify an incorrect configuration betweenthe expected number of the connection components and the actualconfiguration of the connection components between the PSA assembly andthe server rack based on the parameters.
 3. The power system of claim 2,wherein the PSC is further configured to generate a system event log inresponse to the identification, by the processor, of the incorrectconfiguration.
 4. The power system of claim 3, wherein the PSC isfurther configured to periodically transmit the system event log to amanagement module associated with a data center.
 5. An apparatus,comprising: a power shelf controller (PSC) configured to: store a powershelf configuration record that includes parameters for a particulartype of a server rack; prevent energization of direct current (DC) busbars of the server rack based a power shelf configuration associatedwith a power shelf assembly and a power sequencing of a power supplyunit (PSU) of the apparatus; and transmit the parameter to aprogrammable component of the apparatus, the parameters of the powershelf configuration record comprising a number of whips, a number ofPSUs, a PSU capacity, or a data center type in which the server rack isinstalled; wherein the programmable component is configured to: receivethe parameters in response to a bootloader process of the PSC; make acomparison, based on the parameters, of an expected number of connectioncomponents between the apparatus and the server rack and an actualconfiguration of the connection components between the apparatus and theserver rack; and set a flag associated with the PSU identifying anautomatic power on in response to the comparison.
 6. The apparatus ofclaim 5, wherein the PSC is further configured to execute a command toupdate a flag indicating that the PSU should be powered on based on thecomparison.
 7. The apparatus of claim 5, wherein the PSC is furtherconfigured to generate a system event log in response to a swap outoperation of the PSU for an other PSU in the apparatus.
 8. The apparatusof claim 7, wherein the programmable component is further configured toperiodically compare the expected number of connection componentsbetween the apparatus and the server rack and the actual configurationof the connection components between the apparatus and the server rackto identify the swap out operation of the PSU for the other PSU.
 9. Theapparatus of claim 5, wherein the PSC is configured to update the powershelf configuration record based on instructions received via a networkcommunication port of the apparatus, the update of the power shelfconfiguration record including a further update to the parameters. 10.The apparatus of claim 5, wherein the power shelf configuration recordis formatted according to a format associated with the PSC.
 11. Theapparatus of claim 5, wherein the apparatus is further configured tocontinue to provide DC power to the DC bus bars of the server rack inresponse to removal of the PSC.
 12. The apparatus of claim 5, whereinthe power shelf configuration record is stored in non-volatile memoryassociated with the apparatus.
 13. A computer-implemented method,comprising: maintaining a power shelf configuration record that includesparameters for a particular type of server rack and that identifies anexpected configuration of power supply units (PSUs) and connectioncomponents to use with the particular type of the server rack;preventing energization of direct current (DC) bus bars of the serverrack based on a power shelf configuration associated with a power shelfassembly (PSA) of the server rack and a power sequencing of the PSUs;transmitting the parameters to a programmable component the parametersof the power shelf configuration record comprising a number of whips, anumber of the PSUs, a PSU capacity, or a data center type in which theserver rack is installed; and enabling, via the programmable component,execution of a power supply on command for the PSUs based on acomparison of the expected configuration and an actual configuration ofthe power supply units (PSUs) and connection components of a server rackof the particular type.
 14. The computer-implemented method of claim 13,wherein the power shelf configuration record includes a record checksumand a header checksum for use in determining integrity of the powershelf configuration record.
 15. The computer-implemented method of claim13, wherein the PSA further includes a backup battery unit (BBU) that isconfigured to supply DC power to the server rack in response to anindication of loss of power from a first AC power source and during atransition to a second AC power source.
 16. The computer-implementedmethod of claim 13, wherein the parameters of the power shelfconfiguration record identifies a particular number of backup batteryunits (BBUs) associated with the PSA.
 17. The computer-implementedmethod of claim 13, wherein a PSU of the PSUs further comprises anautomatic transfer switch power supply unit (ATSPSU) having ATSPSUfirmware configured to be updated without interrupting DC power to theDC bus bars of the server rack.
 18. The computer-implemented method ofclaim 13, wherein the PSA further comprises a backup battery unit (BBU)having BBU firmware configured to be updated without interrupting DCpower to the DC bus bars of the server rack.
 19. Thecomputer-implemented method of claim 13, further comprising generating asystem event log identifying a health status for the PSUs.